Christophe Calnibalosky

Dassault Aviation

DGT/DTA/IAP

78 Quai Marcel Dassault

92214 Saint-Cloud France

e-mail : christophe.calnibalosky@dassault-aviation.fr

 

Title: Methods and tools for smart electromagnetic antenna integration

 

Extensive use of prediction code in the industry

 

A significant progress has been yielded over recent years, thanks to the improvement of computers and algorithms.

 

Today, hybrid methods can solve a wide diversity of EM problems, combining numerical methods for small size (by comparison to the wavelength) and complex sub-domains, and asymptotic methods for large size regular parts of the computational domain.

 

The way to distribute a computed geometry under different computational techniques requires a specific skill, in order to limit the effect of physical approximations. Typical results illustrate the effectiveness of these methods such as:

·    antenna patterns computed using uniform theory of diffraction with an high speed ray tracing,

·    radiation patterns and impedance computation using boundary element method.

 

The accuracy of hybrid methods has been demonstrated in canonical problems. Today, these methods are efficiently used on industrial problems and can predict the radiation of complex antennas mounted on air vehicles.

 

Various applications are under interest:

·    optimization of antenna location,

·    antenna field isolation,

·    impedance inputs and mutual impedance between antennas,

·    control of field distribution and of coverage pattern.

 

New trends

 

New challenges are the design of optimized electromagnetic windows with regards to numerous constraints such as the aeromechanics environment (vibrations, deflection), the thermal and chemical environment, the radar signature (for military aircraft), radio frequency transparency.

 

To achieve this design, the integration methodology brings into play an equipment model and an aircraft model to be able to predict the behavior of antennas at the earliest design stage: the equipment model is locally representative of the antenna (feeding, materials...), the aircraft model surrounds the RF equipment. These models are connected thanks to the reciprocity theorem. The benefits of this methodology are a saving of computation time while reusing antenna models, and a simpler and more rigorous interface between the equipment design and its integration.

 

 

 

 

Example: computation of UHF antenna on Falcon business jet